Insulating materials are widely used to insulate piping, valves, and related components in both hot and cold applications. Insulation is used both to retain the heat or cold of the substance within the system, and to protect persons from injury caused by direct contact with an extremely hot or cold surface. This type of insulation can be made and installed in several ways. Cloth or fabric insulation may be wrapped around the item to be insulated. A type of plaster or paste material that hardens as it dries may be formed about pipes. Blocks of insulating material may be cut or formed to fit over pipes and other items.
These types of pipe insulation are widely used and work well for relatively small diameter piping. For example, in most situations, a four inch or eight inch pipe can be insulated using any of the previously mentioned methods. The particular type of material used often depends upon the application. High temperature materials may require a different type of insulation than low temperature materials. Nevertheless, when the piping diameters are relatively small (e.g., one foot or less), traditional insulating methods tend to work well.
When blocks of insulating material are used with relatively small diameter piping, it is common to cut or form the insulation in two sectional pieces. Each piece would cover approximately one-half the surface area of the pipe. These two blocks of insulation may be secured to the pipe using a variety of methods, such as mastic, wrapping with cloth or fabric, or with metallic bands.
Some low temperature applications require a great deal of insulating material. For example, a liquefied natural gas (LNG) terminal may require 10,000 to 55,000 lineal feet, or more, of mostly large-diameter piping to be insulated. Because LNG is a very low temperature material (approximately minus 259° F.), and because of the long and large-diameter piping runs, it is important to achieve very good insulation on the piping runs. The cut or formed block method described above works well in such applications, in that it provides a good insulating seal, and the thickness of the blocks can be varied to provide as much, or as little, insulation as required by a particular job. There is, however, one important limitation of the cut or formed block process described above.
When insulation blocks are created to cover one-half of a pipe's circumference, the pipe cannot be very large. When pipe diameters reach or exceed one foot, this method no longer works well, because it requires very large blocks, and creates a great deal of waste because so much of the blocks must be cut away to fit the pipe. This problem is reduced if instead of using two cut blocks, four are used, with each block covering approximately ¼ of the circumference of the pipe. Yet even using four cut blocks will require large blocks and create a great deal of waste, as piping sizes get larger.
To deal with this problem, the number of cut or formed blocks can be increased. As more blocks are used, the curvature required for each block decreases, thus decreasing the amount of material that must be removed from the blocks. This reduces waste, which is a desirable result. This approach has been used in applications with pipe diameters larger than one foot, and works well even for very large bore piping, such as applications with pipe diameters of three feet or more. As the pipe diameter increases, the number of blocks used to cover the full circumference of the pipe increases.
There is, however, a substantial trade off in using this practice. For a given length of pipe, a large number of individually cut or formed insulation blocks is needed. If, for example, twelve blocks are used to cover the full circumference of a particular pipe, then twelve blocks must be cut or formed for each length of pipe. It becomes a very labor intensive process.
One type of material used to insulate low-temperature applications is cellular glass, a material made of foamed silica glass melted at high temperatures. One product of this type is manufactured by Pittsburgh Corning Corporation and sold under the trademark FOAMGLAS®. Cellular glass is a vapor impermeable, fireproof, material with very good insulating qualities. Cellular glass is created in blocks, typically 18 inches wide by 24 inches long and in varying thickness, ranging from about 2 to 6 inches. In some applications, such as large LNG terminals, the insulation specifications require a greater thickness than can be achieved with a single layer of cellular glass cut blocks. Two layers of cellular glass blocks, therefore, may be used in such applications.
To appreciate the labor intensive nature of insulation block preparation for large diameter piping applications, consider an LNG terminal with 15,000 feet of pipe that must be insulated. Assume further that twelve cut blocks will be used to cover the pipe circumference. If the blocks are two feet in length, the job will require 90,000 individually cut or formed insulation blocks, per layer. If two layers are required for the job, a somewhat common situation, nearly 200,000 individually cut or formed blocks would be needed. Some jobs have over 50,000 lineal feet of piping. Such a job might require 500,000 or more cut blocks.
A better means of creating the required insulation blocks was needed. In the traditional process, an operator manually fed uncut cellular glass blocks through a vertical band saw, an annular saw, or some other type of saw to make an angled or curved cut. The blocks were then manually fed through further cutting or grinding steps to finish the block. The blocks created through this process are curved sectional shaped, with the inner surfaces curved to match the curvature of the outer surface of the pipe, and their outer surfaces curved to provide uniform insulation thickness. That means each final block had to be cut in some respect on its four largest surfaces. That is, each side had to be cut at an angle (to create the curved sectional shape), and the inner and outer surfaces had to be cut in a curved (i.e., convex or concave) fashion. In addition to the labor intensive nature of this work, the process included so many individual operator-performed steps that the risk of irregularities was substantial. A minor error or variation by an operator might result in poor fit or blocks that had to be discarded.
The present invention provides an automated machine for creating the needed insulation blocks. It allows for automated operation, and has the potential to generate cut blocks faster than operators can remove them from the machine. The invention greatly reduces the time and labor required to produce cut cellular glass insulation blocks, while providing consistent and uniform results. The invention also greatly enhances operator safety.
In a preferred embodiment, the present invention includes a feed conveyor; an adjustable angle vertical bandsaw positioned adjacent to the feed conveyor, such that insulation blocks are fed to the bandsaw by the feed conveyor; a cut block conveyor; an upper carriage positioned above the cut block conveyor, said upper carriage comprising a pull foot operatively connected to a pull foot ram, a first outer push arm operatively connected to a first push arm ram, and a second outer push arm operatively connected to a second push arm ram; a transport ram operatively connected to the upper carriage; a lateral separation assembly comprising a lower carriage operatively connected to a lower ram, said lower carriage further comprising at least two lateral drive belts and a mechanical stop; first and second grinding lines; a first adjustable angle side grinder positioned to grind an uncut side of a block moving along the first grinding line; a second adjustable angle side grinder positioned to grind an uncut side of a block moving along the second grinding line; a convex upper grinder positioned to grind an upper surface of a block moving along the first grinding line; a concave lower grinder positioned to grind a lower surface of a block moving along the first grinding line; a concave upper grinder positioned to grind an upper surface of a block moving along the second grinding line; and, a convex lower grinder positioned to grind a lower surface of a block moving along the second grinding line.
In a preferred embodiment, the invention further includes the steps of determining the number of curved sectional shaped insulation blocks needed to cover a full circumference of an item to be insulated; calculating a block side angle based on the number of curved sectional shaped insulation blocks needed to cover a full circumference of an item to be insulated; setting an angled vertical bandsaw to produce a cut at the block side angle; setting a side milling tool to machine an uncut side of an insulation block at the block side angle; cutting with the angled vertical bandsaw one side of the number of curved sectional shaped insulation blocks needed to cover a full circumference of an item to be insulated; machining with the side milling tool the uncut sides of cut blocks; arranging the cut and machined blocks in a circular pattern, with the blocks arranged side-to-side; measuring an inner diameter of the circle of arranged blocks; comparing the measured inner diameter to a specified project diameter; if the measured inner diameter is not approximately equal to the specified project diameter, making adjustments to the angle of cut of the vertical bandsaw and the angle of machining of the side milling tool to produce cut and machined blocks that produce a circle with a measured inner diameter that is approximately equal to the specified project diameter; repeating this process as necessary until the measured inner diameter is approximately equal to the specified project diameter; and, cutting and machining the required number of insulation blocks for the project.